import cv2 as cv
import numpy as np

img = cv.imread('../pic/sudoku.png')
gray = cv.cvtColor(img, cv.COLOR_BGR2GRAY)
edges = cv.Canny(gray, 50, 150, apertureSize=3)
lines = cv.HoughLinesP(edges, rho=1, theta=np.pi / 180, threshold=100, minLineLength=100, maxLineGap=10)

for line in lines:
    x1, y1, x2, y2 = line[0]
    cv.line(img, (x1, y1), (x2, y2), (0, 255, 0), 2)

cv.imshow('houghlines5', img)
cv.waitKey()
cv.destroyAllWindows()
